pcs 0.8.4

/* Copyright (c) Fortanix, Inc.
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */
use pkix::pem::PEM_CRL;
use serde::{Deserialize, Serialize};
use std::path::PathBuf;

#[cfg(feature = "verify")]
use {
    mbedtls::alloc::List as MbedtlsList,
    mbedtls::x509::Certificate,
    std::convert::TryFrom,
    std::ffi::CString,
    std::ops::Deref,
};

use crate::io::WriteOptions;
use crate::io::{self};
use crate::{DcapArtifactIssuer, Error, Unverified, VerificationType, Verified};

#[derive(Clone, Serialize, Deserialize, Debug, Eq, PartialEq)]
pub struct PckCrl<V: VerificationType = Verified> {
    pub(crate) crl: String,
    ca_chain: Vec<String>,
    #[serde(skip_serializing)]
    _type: V,
}

impl PckCrl<Unverified> {
    pub fn new(crl: String, ca_chain: Vec<String>) -> Result<PckCrl<Unverified>, Error> {
        let crl = PckCrl {
            crl,
            ca_chain,
            _type: Unverified,
        };
        Ok(crl)
    }

    #[cfg(feature = "verify")]
    pub fn verify<B: Deref<Target = [u8]>>(
        self,
        trusted_root_certs: &[B],
    ) -> Result<PckCrl<Verified>, Error> {
        // Check if ca_chain is a valid chain
        let (chain, root) = crate::create_cert_chain(&self.ca_chain)?;
        let chain: MbedtlsList<Certificate> = chain.into_iter().collect();
        let root = std::iter::once(root).collect();
        let mut err = String::default();
        Certificate::verify(&chain, &root, None, Some(&mut err))
            .map_err(|e| Error::InvalidCrl(e))?;

        // Check if the root in self.ca_chain is in `trusted_root_certs`
        crate::check_root_ca(trusted_root_certs, &root)?;

        // Check if first entry in CA list signed CRL
        let crl = crate::as_mbedtls_crl(&self.crl)?;
        let crl_signature = crl.signature().map_err(|e| Error::InvalidCrl(e))?;
        let crl_tbs = crl.tbs_raw().map_err(|e| Error::InvalidCrl(e))?;
        let mut hash = [0u8; 32];
        mbedtls::hash::Md::hash(mbedtls::hash::Type::Sha256, &crl_tbs, &mut hash).unwrap();

        let pck_ca = self
            .ca_chain
            .first()
            .ok_or(Error::InvalidPck("Pck CRL doesn't have a CA".into()))?;
        let pck_ca = CString::new(pck_ca.as_bytes()).map_err(|_| Error::InvalidCaFormat)?;
        let mut pck_ca = Certificate::from_pem(pck_ca.as_bytes_with_nul())
            .map_err(|_| Error::InvalidCaFormat)?;
        let pck_ca = pck_ca.public_key_mut();
        pck_ca
            .verify(mbedtls::hash::Type::Sha256, &hash, &crl_signature)
            .map_err(|e| Error::InvalidCrl(e))?;

        // Sanity check on Pck CRL
        self.ca()?;

        let PckCrl { crl, ca_chain, .. } = self;
        Ok(PckCrl::<Verified> {
            crl,
            ca_chain,
            _type: Verified,
        })
    }

    pub fn read_from_file(input_dir: &str, ca: DcapArtifactIssuer) -> Result<Self, Error> {
        let filename = Self::filename_from_ca(ca);
        let crl: Self = io::read_from_file(input_dir, &filename)?;
        Ok(crl)
    }
}

impl<V: VerificationType> PckCrl<V> {
    pub(crate) fn filename_from_ca(ca: DcapArtifactIssuer) -> String {
        match ca {
            DcapArtifactIssuer::PCKProcessorCA => String::from("processor.crl"),
            DcapArtifactIssuer::PCKPlatformCA => String::from("platform.crl"),
            DcapArtifactIssuer::SGXRootCA => String::from("root.crl"),
        }
    }

    #[cfg(feature = "verify")]
    pub fn filename(&self) -> Result<String, Error> {
        Ok(Self::filename_from_ca(self.ca()?))
    }

    #[cfg(feature = "verify")]
    pub fn write_to_file(
        &self,
        output_dir: &str,
        option: WriteOptions,
    ) -> Result<Option<PathBuf>, Error> {
        let filename = self.filename()?;
        io::write_to_file(&self, output_dir, &filename, option)
    }

    pub fn write_to_file_as(
        &self,
        output_dir: &str,
        ca: DcapArtifactIssuer,
        option: WriteOptions,
    ) -> Result<Option<PathBuf>, Error> {
        let filename = Self::filename_from_ca(ca);
        io::write_to_file(&self, output_dir, &filename, option)
    }

    pub fn crl_as_pem(&self) -> &String {
        &self.crl
    }

    pub fn crl_as_der(&self) -> Result<Vec<u8>, Error> {
        pkix::pem::pem_to_der(&self.crl, Some(PEM_CRL)).ok_or(Error::InvalidCrlFormat)
    }

    pub fn certificate_chain(&self) -> &Vec<String> {
        &self.ca_chain
    }

    #[cfg(feature = "verify")]
    pub fn ca(&self) -> Result<DcapArtifactIssuer, Error> {
        let issuer = crate::as_mbedtls_crl(&self.crl)
            .and_then(|crl| crl.issuer().map_err(|_| Error::InvalidCrlFormat))?;
        let issuer = DcapArtifactIssuer::try_from(issuer.as_str())?;

        if let DcapArtifactIssuer::SGXRootCA = issuer {
            // PCK Crls should be signed by the PCKPlatformCA or PCKProcessorCA
            return Err(Error::InvalidCrlFormat);
        }
        Ok(issuer)
    }
}

#[cfg(test)]
mod tests {
    #[cfg(all(not(target_env = "sgx"), feature = "verify"))]
    use {super::PckCrl, crate::DcapArtifactIssuer};

    #[cfg(all(not(target_env = "sgx"), feature = "verify"))]
    #[test]
    fn read_pck_crl() {
        let crl =
            PckCrl::read_from_file("./tests/data/", DcapArtifactIssuer::PCKProcessorCA).unwrap();
        assert_eq!(crl.ca().unwrap(), DcapArtifactIssuer::PCKProcessorCA);
        let root_ca = include_bytes!("../tests/data/root_SGX_CA_der.cert");
        let root_cas = [&root_ca[..]];
        crl.verify(&root_cas).unwrap();
    }

    #[cfg(all(not(target_env = "sgx"), feature = "verify"))]
    #[test]
    fn serialize_deserialize_pck_crl() {
        let crl =
            PckCrl::read_from_file("./tests/data/", DcapArtifactIssuer::PCKProcessorCA).unwrap();

        let serialized_bytes = serde_json::ser::to_vec(&crl).unwrap();
        let crt_deserialized: PckCrl<crate::Unverified> =
            serde_json::de::from_slice(&serialized_bytes[..]).unwrap();
        assert_eq!(crt_deserialized, crl);
    }

    #[cfg(all(not(target_env = "sgx"), feature = "verify"))]
    #[test]
    fn read_platform_pck_crl() {
        let pckcrl =
            PckCrl::read_from_file("./tests/data/", DcapArtifactIssuer::PCKPlatformCA).unwrap();
        let root_ca = include_bytes!("../tests/data/root_SGX_CA_der.cert");
        let root_cas = [&root_ca[..]];
        pckcrl.clone().verify(&root_cas).unwrap();
        assert_eq!(pckcrl.ca().unwrap(), DcapArtifactIssuer::PCKPlatformCA);
    }
}